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Guillain–Barré syndrome

contributed by Gagandeep Singh on November 7, 2009

System: Peripheral Nervous System
Section: Syndromes

Guillain–Barré syndrome (GBS) is defined as heterogeneous group of autoimmune polyradiculopathy, involving sensory, motor and autonomic nerves.

Clinical presentation

Classical presentation of GBS includes symmetrical ascending muscle paresis or palsy, areflexia or hyporeflexia along with variable degree of sensory or autonomic involvement.

Most cases are preceded by upper respiratory tract infections or diarrhoea 1-3 weeks before its onset, most commonly caused by campylobacter. Molecular mimicry with the bacterial agents is thought to cause the autoimmunity.

Several subtypes have been described including:

  • axonal sub types
    • acute motor axonal neuropathy(AMAN)
    • acute motor sensory axonal neuropathy (AMSAN)
  • regional GBS syndromes
    • Miller Fischer variant
      • characterized by ataxia, areflexia without weakness and ophthalamoplegia.
      • anti GQ1b antibodies are present in most cases

GBS is diagnosed by combination of clinical presentation,CSF study and electrophysiological criteria. CSF abnormalities are characterized by increase protein with pleocytosis. Nerve conduction abnormalities include slow or blocked nerve conduction, prolongation of distal latency and f-waves.GBS is primarily managed with IV immunoglobulins or plasmapharesis along with supportive measures.

Radiographic features

Radiologic studies are ordered to exclude other causes and in cases where nerve conduction studies and CSF examination are equivocal.

MRI

MRI of the spine is most useful helps excluding other aetiologies like transverse myelitis and compressive causes of polyradiculopathy. Typical findings in a case GBS include nerve root thickening and enhancement surrounding the medullary cone extending along the  cauda equina. These findings are as a result of break down in the blood brain barrier. The most common site of enhancement in GBS is considered to be anterior nerve roots. MRI is a sensitive but non-specific examination diagnoses is reached by correlating clinical findings with patterns of nerve root enhancement and nerve conduction findings.

Differential diagnoses